Architect of a contentious manifesto
Delays to Higher Still were "to ensure teachers are prepared and the resources are available".
She pledged staff development would be an entitlement for all teachers but promised to consult with teachers and councils.
"Labour will establish rigorous and systematic school evaluation that recognises staff development as a key plank in raising standards overall, " she told Catholic heads. Teachers had "nothing to fear" from appraisal.
Mrs Liddell also trailed the "full-service school", recently launched by Donald Dewar, the Scottish Secretary, a re-examination of promotion structures in schools, and management training for aspiring heads.
Other pledges included cutting class sizes in the first three years of primary and extending nursery places to three-year-olds.